This invention concerns improvements in and relating to a cathode for a chlor-alkali cell, a method for making said cathode, and a method for lowering the hydrogen overvoltage of a chlor-alkali cell.
Production of caustic and chlorine by electrolysis of brine is well known in the art. The electrolysis is carried out in an electrolytic cell which consists of general of an anode, a cathode, an anode compartment and a cathode compartment. In one of the more recent types of such an electrolytic cell, the two compartments are separated from one another by a fluorine-containing cation exchange membrane.
Such an electrolytic cell can be operated more efficiently and economically as the current efficiency is increased, and as the operating voltage is lowered. Inasmuch as very larger quantities of caustic and chlorine are produced by electrolysis of brine daily, even very small improvements in the current efficiency and operating voltage of chlor-alkali cells will lead to saving of large amounts of money and conservation of large amounts of energy.
The operating voltage of a chlor-alkali cell is made up of a number of component parts, of which one is the voltage drop at the cathode, known as the hydrogen overvoltage. A lowering of the hydrogen overvoltage will result in lowering of the overall cell voltage and consequently make the process more economical.
It is therefore an object of this invention to provide an improved cathode for a chlor-alkali cell and a method for making that cathode.
It is another object of this invention to provide a method for lowering the hydrogen overvoltage of a chlor-alkali cell.